Automatic reset circuit breaker



W. H. FRANK AUTOMATIC RESET CIRCUIT BREAKER April 7, 1936.

Filed April 21, 4 Sheets-Sheet l ATTOR-NEY April 7, 1936.

W. H. FRANK AUTOMATIC RESET CIRCUIT BREAKER Filed April 21, 4 Sheets-Sheet 2 INVENTOR. v MMJM ATTORNEY.

April 7, 1936. w. H. FRANK 2,036,266

AUTOMATIC RESET CIRCUIT BREAKER INVENTOR.

Am Q, l

ATTORNEY.

April 7, 1936. w. H. FRANK AUTOMATIC RESET CIRCUIT BREAKER Filed April 21,

4 Sheets-Sheet 4 INVENTOR. w WJ/ 06.60

ATTORNEY.

Patented Apr. 7, 1936 PATENT OFFICE AUTOMATIC RESET CIRCUIT BREAKER William.H.' Frank, Detroit, Mich., assignor to Bulldog Electric Products Company, Detroit, Mich., a corporation of West Virgint.

Application April 21,

13 Claims.

This application relates to automatically "resetting circuit breakers and can best be understood with reference to my copending application Serial No. 667,149, filed April 21, 1933.

In the above identified applications there has been disclosed an automatically resetting circuit breaker which may operate in such a fashion that a continuous cycle of overload release and automatic reset will occur so long as there exists on the controlled circuit an overload condition. The circuitbreaker of thatapplication includes a spring motor which continuously functions to release and reset the breaker, and which therefore is apt to run down. It is therefore considered desirable to provide for such a motor, a means for maintaining the spring motor continuously wound, and/or b means whereby the condition of the spring will be brought to the attention'of the householder, when the spring has run down to a dangerous point, and the inventions of this application aim to provide such means a and b.

The means b is so constructed that it operates, when the spring has run down, to leave the breaker in the open circuit position. That is to say, the spring will always be of suflicient strength to open the circuit, on overload or short circuit, for safetys sake, but if its strength runs down, it will not operate to close the circuit after its last circuit opening operation.

The invention further aims to provide means automatically operable to reveal the condition of the breaker controlled circuit, the means having selectively visible indicia, such as On, Wind and Off.

Further objects will presently appear upon reference to the'following detailed description of preferred embodiments of the inventions, these embodiments being shown in the appended drawings. In these drawings- Fig. l is a top plan View of an automatically resetting circuit breaker provided with an automatic spring rewinding device.

Fig. 2 is a section as if on line 2-2 of Fig. 1.

Fig. 3 is a section as if on line 3-3 of Fig. 1.

Fig. 4 shows a spring detent and is a section as if on line 44 of Figures 1 and 5.

Fig. 5 is an end elevational section of the device as if from the left of Fig.1.

Fig. 6 is a right end view of the same.

Fig. '7- is an elevational section of the same as if on line 'll of Fig. 5.

Fig. 8 is a similar view as if on line 8--9 of Fig. 6.

Fig. 9 is a view like that of Fig. 2 but with the parts shown in Overload release position.

1933, Serial No. 667,115].

Fig. 10 is a view like that of Fig. 9 but with the parts shown in an Off position, due to manual control operation.

Fig. 11 is a view like that of Fig. 9 but with the parts shown in an Oif position produced by manual reset latching.

Fig. 12 is a section on line l2-i2, Fig. 14 and shows a breaker equipped with means for insuring the breaker being left in open circuit position, when the operating spring has run down, the partsbeing shown in closed circuit position.

Fig. 13 is a view of the device of Fig. 12, parts being shown in open circuit position, and is a section on line i3l3, Fig. 14.

Fig. 14 is a cut away end view of the device.

Fig. 15 shows a modified form of detail, providing an indicator.

The breaker of Figures 1 to 11 The automatically resetting breaker of these figures is characterized by the fact that the thermal element moves in a direction normal to the operating shaft, and functions thru a separate release element to release the shaft for trip and reset of the breaker. The breaker parts are mounted upon a base "H of insulating material and are enclosed within a cover I la, also of insulating material, the cover having slots through which projects the three manually engageable parts of the breaker, namely; the winding drum 3 12, the manual control handle 14, and the manual reset latch handle '15. The breaker parts will now be described specifically.

Pivotally mounted on an axle pin 16, to and between the upstanding fixed framed plates 11, is the breaker contact arm 18, the arm having a contact it for engaging the fixed contact 80 of the breaker. As shown, the line is connected to the arm, but it may well be connected to the contact 8%, in which case the arm would be connected to the load thru the thermal element. Pivotally connected by an axle pin 8! to two upstanding parts of the breaker contact arm 18 are connecting rod links 322 which at their upper ends are connected to a crank 83 formed on the breaker operating shaft t l. the latter being trunnioned in aligned bearing holes of the upstanding framed plates ii. It is observed that rotation of the operating shaft 84 operates, through the medium of the crank 83 and the connecting rod links 82, to move the contact arm it to and from contact making and breaking position, and the crank and links serve as a toggle clamp for the arm, when in On position.

One end of the operating shaft is bent perpendicuiarly from the axis of the shaft to provide a holding crank 85 adapted to be held by one or another of the stops actuated by the thermal element referenced generally T. The latter is connected at one end, by a lead, to contact 80, and at the other, to the load.

The On holding stop, that is to say, the stop which holds the holding crank 85 in the On position, Figs. 1 to 8, is referenced 86 and is in the nature of a lug provided on a plate 81 whose end is connected to the bimetallic thermal element .T so as to be reciprocated, normal to the shaft, by the thermal element, which warps normal'to the shaft, the thermal element including relatively electrically and mechanically connected bimetallic strips 88 insulated from the plate 81 by an insulating strip 89, it being observed that the connection between the thermal element and the plate 8! includes a pivot 89a, which permits relative movement of the thermal element and the whereas when the crank is in the Off position, the end of the latter will engage the upperleft hand corner of the stop 90. I

The plate 81 is fixed to the upper end of a support 92 mounted on a bracket 92a in turn positioned on a block of insulating material 93, disposed in a depression in the upper surface of the base and mounted in key and groove runways therein and so proportioned as to .be able to slide in such depression in a direction normal to the axis of the operating shaft 84. This block also supports the thermal element fT.

For manually sliding the block 93 in its depression, there is. provided an actuating device whose handle has been previously referred to as a manual control handle I4. This handle is jourjecting upwardly from the block 93, and it will be observed that movement of the actuating handle I4 slides the block 53 in its depression. For latching the block 93 in the "On position of Fig. 12, or in the Off position of Fig. 10, thereis provided a spring 91 (Fig. 10) adapted to engage one or another of a pair of notches 98, formed in the lower surface ofthe block.

On the end of the operating shaft 84 opposite that end thereof, which is formed as a holding crank 85, is a drum, previously referenced I2, and

containing a clock spring I 00, wound upon the end of the operating shaft and having one end fixed to the shaft and the other end fixed tothe drum It. This spring tends to rotate the operating shaft clockwise (Fig. 2) and its influence is opposed by the stops 88 and.90, previously mentioned.

For winding the spring, the operator may manually rotate the. drum which is rotatably journalled on the shaft and is held against reverse rotation by a ratchet wheel I03 fixed to the drum and disposed between a frame plate 11 and the drum, as indicated in Fig. 1. A clock work pawl I04 cooperates with the ratchet to prevent movement of-the drum in the counterclockwise direc-.

tion as the drum is being rotated clockwise to wind the spring, it being observed that the drum can be wound by moving it with the thumb.

ing from the spring.

The stops Automatically operating spring rewinding means are also provided and these will presently be described.

In order to provide a manual reset latch which maintains the breaker open and prevents the breaker from being reset in any manner except manually, there is slidably mounted on one of the upstanding frame plates 17 a plate I01 guided on the upstanding frame plate through the medium of the slots I08 receiving pins I09 project- The latching plate is formed with an extension III adapted to be moved with the plate to underlie and project beyond the Off stop 90, and when so moved, to prevent rotation of the holding crank 85 from the Off position to the On position. The spring II2 cooperates with notches H3 in the lower edge of the plate M1 to define positions of the latter.

The operations of the breaker per se, apart from the automatic rewind means to be described, will now be described in complete detail. Assume the parts to be in On position. At this time the holding crank 85 engages and is disposed under the On stop 86, and the operating shaft and its associated parts are held in the On position, with the contact arm I8 in a horizontal position, so that contact I9 engages contact 80, the parts being held against the influence of the spring I00 which tends to rotate the operating shaft clockwise. It is observed that the thermal element occupies such a position on normal load that the stop 86 is directly in the path of holding crank 85.

Upon the arising of an overload, the thermal 1 element T will warp normal to the operating shaft 84, that is to say, to the left of Fig. 2, sufliciently to move stop 86 out of the path of the holding crank 85. The spring I 00 consequently rotates the parts clockwise with an extremely rapid movement. Such rotation causes an upward pull on the connecting rod links 82 and pivots contact arm I8 to the position of Fig. 13 from the position of Fig. 12; that is to say, it opensthe circuit. When thermal element T warped to the left of Fig. 2, it placed stop 90 in the path of crank 85. Consequently, the crank rotates on overload but one-half turn, and is engaged by thestop 90, to restrain further rotation of the parts.

When the. circuithas been opened sufiiciently long for the thermal element T to cool and warp back to its original position, the stop will move towards the right, out of the path of crank 85, and the latter will be released. Ac-

cordingly, the operating shaft will be free to' rotate and the spring I00 will rotate the shaft another half-turn clockwise to close the circuit and to bring contact arm once more under and against stop 86, which in the meantime had moved with plate 81 to the right of Fig. 9.

. If the overload still is on the line, this cycle of operations will be repeated, and will continue so long as the overload is in existence or until the operator manually opens the circuit breaker.

It willconsequently be seen that the circuit to the left, Fig. 2, to the positionof Fig. 10.

Such movement 'of the handle causes the .block 93 to. slide to the left and this movement, carrying the thermal element T and the plate 81 a,os6,266

with the block,takes the stop 86 out of the path of the crank 85 and places the stop 90 in the path of the crank 85. The spring I rotates the operating shaft to Off position. To restore the parts to On position, the actuating handle is moved back to the position of Fig. 2

' which serves to move stop 90 away from crank 85, freeing the latter and the shaft for movementby the spring I00, which then rotates the shaft until the crank 85 is engaged by the stop 86, which had moved into the path of the crank.

In the event it is desired to latch the breaker in the Off position, the manual reset latch handle 15 is moved from the position of Fig. 2 to the position of Fig. 11. Such movement of the handle, and obviously of the plate I01, projects the part III into a position directly into the path of crank 85. The manual switching handle 14 is then moved to Ofi position and crank 85 rotates, and is ultimately held in Off position by part I I I. Reset may be accomplished only manually, by moving latch back to On position manually.

The automatic rewinding means: Figs. 1-11 The automatic rewinding means disclosed in this application and which per se represents part of the novelty that this application possesses over the prior application above referred to, includes a solenoid which is automatically energized whenever the contact arm 18 is moved to Off position by the spring motor. The solenoid circuit is in parallel with the contact arm and thermal element circuit and includes a pair of contacts which are caused to engage by movement of the contact arm to an open circuit position, the solenoid circuit contacts being in series with the solenoid.

.The solenoid operates a plunger which is connected to the ,drum of the spring motor thru .suitable gearing and the operation is such that whenever the contact arm is moved to Ofi position, the solenoid is energizedand the drum is rotated for rewinding the spring. A coil spring on the plunger returns the solenoid plunger to its original position when the solenoid becomes de-energized due to return of the contact arm from Off position to On position.

The automatic rewinding mechanism will now be described specifically.

Suitably mounted on the base H is a solenoid I20 electrically connected to the line side of the contact arm 18 by a lead I2I and electrically connected to a binding post I22 by a conductor I23. From this binding post there extends a conductor I24 which leads to an anchoring screw I25,- and anchored to this screw is a leaf spring I28 bearingon its upper surface a contact I21, and on itslower surface a striker part I28, the latter being insulated from the leaf spring I26 by insulation at I29. The striker part lies directlyover the contact arm 18 and is adapted. to be engaged by the contact arm when the latter moves to Off position. When the striker arm is engaged by the contact arm, the leaf spring I28 moves upwardly from the position of Fig. 1, so that contact I21 thereof, engages a contact I3I fixedly mounted and electrically connected to an anchoring screw I32. This screw is connected by a conductor I33 to a binding post I34, which in turn is connected by a lead I35, Fig. 2 to that binding post I38 of the thermal element T to which the load conductor, Fig. l, is con- 7 nected. i

It will be seen that when the contact arm 18 moves upwardly Fig. 1, it will close an electrical circuit from the line conductor to the load conductor through the solenoid I20, to energize the latter.

It is observed that binding post I34 may be connected directly to the other side of the line; in which case the solenoid will be connected directly across the line, shunting the load, when contact arm 18 moves upwardly and causes contacts I21--I3I to engage.

It is further observed, that even when the solenoid is connected in series with the load, by connecting'binding post I34 to the thermal element T, it is so connected only upon the occurrence of an overload or short circuit. Accordingly, since the overload or short circuit has the effect of reducing the load resistance, even in such a case, the solenoid will receive full line voltage, as is of course true of the construction wherein the solenoid binding post I34 is connected to the other side of the line.

Further, it is contemplated to connect the sole noid to the load, and use it and its contacts, not only for rewinding, as here disclosed, but also as the solenoid of my application Serial No. 667,150, filed April 21, 1933; wherein a solenoid, in series with the load, is used for controlling themanual resetting of the circuit breaker. Therefore, it can be said that there is here disclosed, on the principle of incorporation by reference to that application, a single solenoid used for rewinding and for controlling breaker reset.

. When the solenoid is energized, it moves its plunger I40 to the right of Fig. 2 against the influence of the plunger spring I4I which bears against a plate I42 of the solenoid and a pin I43 of the plunger. The remote end of the plunger is in the nature of a. flat strip provided with rack teeth I45 on its upper surface, and having a slot I46 guiding the plunger on a pin I41 fixed to a frame part I48. The rack teeth I45 of the plunger engage a pinion gear I410. rotatably journalled on a jack shaft I49 journalled in frame parts I48 and I50. Also journalled on the jack shaft and suitably fixed to pinion gear MM is a crank I5I whose spring detent I52 is in engagement with the teeth of a ratchet I53 keyed to the jack shaft, the connection between the pinion gear I41 and the jack shaft being a uni-directional one, so that rotation of the pinion I410. in one direction, counterclockwise, Fig. 2, r0- tates the jack shaft counterclockwise, whereas rotation of the pinion I41a clockwise, Fig. 2, does not rotate the jack shaft clockwise. Also keyed to the jack shaft I43 isa large gear I54 which meshes with a small gear I55, journalled on the end of the operating shaft 84, and fixed to the drum 12 so that the drum and the small gear I55 rotate in unison. The connection between the small gear and the drum may be effected in any suitable manner, as for example, by a rivet or pin passed through a wall of the drum and the plate of the gear I55, such means not being shown, since it is well within the purview of the ordinary skilled mechanic.

It is observed at this time that the foregoing return of the plunger due to de-energlzat'ion of the solenoid I and due to the influence of the spring I 4|, does not rotate jack shaft I48 and gears I 54, I55 in a direction reverse from that which they attain when the solenoid is energized and the parts move for drum spring winding. This type of connection is desirable since it gives a one way rotation to the drum I2, regardless of the direction of movement jof the solenoid plunger.

The operation of the parts will readily be observed from the foregoing. Whenever the drum spring I08 causes the operating shaft 84 to rotate clockwise, Fig. 2, with a consequent unwinding of the drum spring, the solenoid is immediately energized to rewind the'spring and restore it to its'original condition, this operation,

however, not affecting the operating shaft 84, or the circuit closing or opening parts.

It is noted that where the solenoid is connected to shunt the load, as previously described, it remains in circuit all the while the breaker is open, even though it had completed its function of rewinding the spring long before the thermal element returns to close the breaker.

The wind demand latch and indicator:

1 Figs. 12 to,15

In these figures, there is shown an auxiliary which has been disclosed in connection with the circuit breaker of Figs. 1 to 11 of this application and which is intended to be used either as an addition to a circuit breaker equipped with an automatic rewinding device or as an auxiliary for a circuit breaker not so equipped. The functions of thevind demand latch and indicator may be briefly described as follows:

In the event the spring motor becomes unwound, or otherwise weakened to such an extent that it can no longer function satisfactorily to rotate theoperating shaft to and from contact making and breaking positions, the contact parts will be so disposed that they will remain in an open circuit position, once they are moved to such a position. While this may cause some inconvenience to the householder, it will at least not endanger the apparatus or circuit which is to be protected by the circuit protective device. Other- Wise, the parts might be left in a closed circuit position, with insuificient power in the spring motor to move them out of this position when an overload occurs.

Accordingly, there is provided and disclosed in these figures, a wind demand latch which latches the parts in open circuit position whenever the condition of the spring motor is such that rewinding of the same is demanded.

The provision of such a device, while in its W11 right desirable, might be considered objec- 1 open circuit position and the householder not told why the circuit breaker does not function. For

These figures show many parts which are identical with the correspondingly referenced parts of Figs. 1 to 11 inclusive. For example, these figures show a base 1I closed by a cover 1Ia through which projects a winding drum 12, a manual switching handle 14, and a manual 01f latch handle 15. An axle pin 18, mounted between frame plates 11, journals a breaker contact arm 18 having a contact 19 adapted to engage a fixed contact 80, and an axle pin 8| on the arm journals connecting rod links 82 which connect the contact arm to a crank 83 of an operating shaft 84, the latter having a holding crank 85 on its end. For holding the crank, there is provided an On'stop 86 formed as a lug on plate 81 in turn connected to the thermal element, the latter including bimetallic strips 88 insulated from the plate 81 by insulation 89 and connected to the plate by a pivot 89a, and there is also provided on the plate 81, an Oil stop 80.

Plate 81 is mounted on a slide block 93, actuated by the handle 14.

Other parts of the breaker which are like corresponding parts of the breaker of Figs. 1 to 11 are not mentioned specifically, it being understood that they are shown and described in connection with the breaker of Figs. 1 to 11.

The wind demand latch per se will now be described specifically.

Passing through a bracket I10 secured to the cover Na and disposed parallel to the operating shaft 84 is an axle pin I1 I, on one of whose ends is keyed a bell crank I12 and on the other of whose ends is keyed a pawl I13. One end of the bell crank is connected at I14 to a coiled tension spring I15 which in turn is connected through a spring tensioning screw at I16 to an extension I11 formed on bracket I10. The pawl I13 is in the path of rotation of the holding crank 85 and co-operates with such crank as follows:

Whenever the crank 85 is rotated from On position towards Oif" position, that is to say, clockwise, Fig. 12, the crank will engage pawl I13. It will pass by the pawl if the strength of the spring in drum 12, that is to say, the spring that rotates the operating shaft on which the holding crank 85 is formed, is greater than the strength of spring I15. If such, be the case, the crank 85 in passing from On to Off position will do nothing more than kick the pawl I13 and rotate the bell crank I12 counter-clockwise against the influence of the spring I15 until the crank 85 passes by the pawl, after which the pawl I13 and the bell crank I12 will return to their normal position, Fig. 12.

If, however, the strength of the operating shaft spring in drum 12 is not greater than the strength of spring I15, as for example when the operating spring has run down and needs rewinding, the holding crank will be prevented from reaching stop 88 by the pawl I13, as seen in Fig. 13, the

crank assuming a rest position somewhere between its On position and its full Off position. The crank, in the position of Fig. 13, has moved far enough to place the contact arm 18 in an Off" position for circuit rupturing but is nevertheless held from reaching its full 0115" position by the pawl.

With the holding crank so positioned, automatic resetting after overload release cannot be effected merely by a return of the thermal element and by a reciprocating movement of plate '81, because, regardless of such movement, pawl I13, as influenced by its spring I15, holds the crank 85 in the position of Fig. 13. In order to accomplish reset, it therefore becomes necessary for the householder to re-wind the spring in drum 12 sufficiently to cause the latter to overcome the strength of spring I15. When this is accomplished, the pawl I13 will release the crank 85 and will permit the latter to assume its full 75 I "Oif position, from where it can be rotated by the spring to On position.

It will thus be seen that Figs. 12 to 14 show a device which maintains the part in open circuit position and prevents them from returning to closed circuit position whenever the spring in drum 12 needs rewinding.

The device of Figs. 12-14 may also be used as a means to limit the number of cycles of operations of the breaker, it being observed that the number of cycles of breaker release and automatic reset is determinable by the relative strengths and tensions of springs not and H5. The latter is adjustable and permits variation of the number of cycles permitted. The last cycle always will not be completed, terminating in a breaker release, without an automatic reset until the spring is rewound.

Further, the holding means can be provided to engage the crank on its path of movement between Oif and On, as well as between On and Ofi, and either manner of relating the holding means to the crank may be used, as desired.

The indicating means, which is automatically operated to indicate the reason for the parts be ing maintained in the open circuit position, is in the nature of an indicator plate I80 formed on one of the arms of the bell crank I12, this plate being adapted to underlie and align with an opening l8! in the cover of the device so as to be visible through the opening 18!. It will be observed that whenever the parts assume the rest position of Fig. 13, with the holding crank 85 held by the pawl I13, the legend Wind is presented to the operator and calls his attention to the, necessity for rewinding the spring in drum '12.

The wind demand latch described in the foregoing might well be considered as a means for limiting the number of cycles of release and reset that may occur, since it will so function.

In Fig. 15 there is disclosed an indicating means having three indicator positions, On, Wind and "Oif. The pawl H3 is replaced by a differently shaped pawl 213, and the plate I80 is replaced by a differently formed plate 280, having On, Wind and Off marked thereon, as indicated, The other parts are the same, and the device operates as follows: The parts, as indicated, are in the On position, with the On part of plate 280 under the window I. When the crank 85 rotates clockwise, on overload, it will engage pawl 213 and move it counterclockwise. If the motor spring is weaker than the spring I15, the plate 280 will move only halfway, to present Wind to the window, and the parts will remain held in open circuit position. If the motor spring is stronger than spring H5,

as is normally the case, the plate 280 will move all the way, to present Off to the window.

This is the normal operation.

trolled by plate 280 and therefore, by the condition of the breaker itself.

Auxiliaries It is'at present contemplated to combine with the devices shown in this application, and the combinations effected through the use of these devices, certain auxiliaries which are not here disclosed but which are disclosed in detail in certain copending applications which are being filed simultaneously herewith.

For example, in application Serial No. 667,149, filed April 21, 1933, there are disclosed in Figs 1 to and 11 to 18, two different forms of circuit breakers and it is at present contemplated to provide either or both of the novel means of this application on either of the forms of circuit breakers. Similarly, it is contemplated to com bine either or both of the novel means of this application with the multi-poleunit of Figs. 19 to 28 of that application and with the controlling breakers of Figs. 19 to 30 of that application.

Further, in application Serial No. 667,150, filed April 21, 1933, there is disclosed an automatically operating 01f holding latch including an elec tro-magnet, which latch operates automatically to hold the contact arm of the circuit breaker in open position, once that arm has been moved to,

open position by the circuit breaker mechanism, the holding being continued until the load consuming device has been taken off or cut out of the line. The Off holding latch of the appli cation just mentioned may be added as an appendage to any of the devices shown in this application.

Further, in application Serial No. 667,152, filed April 21, 1933, there is shown a means for limiting the number of cycles of overload release and automatic reset that can occur before the operator is called upon to reset the device. This auxiliary may be added to any of the breakers here shown, if desired.

Further, various combinations of the features here shown and of the features shown in the copending applications just referred to may be effected, and it is the present intention to cover in this application as well as the applications above referred to, combinations of the devices and auxiliaries specifically shown in those applications with any or all of the devices or combinations here shown.

Now, having described the diiferent forms of breakers, reference will be had to the following claims which determine the scope of the invention, it being expressly understood that the breakers heretofore described and disclosed have been chosen merely as examples, and not as il lustrating all of the possible embodiments of the invention.

I claim:

1.1m automatically releasing and resetting circuit protecting breaker including an enclosing casing, an automatically operating spring means for effecting release and reset cyclic movement of said breaker, and an externally visible indicator automatically moved on release or reset move ment of said spring means for indicating the nature of the latest movementof said means, and

also for indicating when, if at all, the spring means has had its potential energy reduced to an undesirable extent.

2. An automatically releasing and resetting circuit protecting breaker including an enclosing casing, an automatically operating spring means for effecting release and reset cyclic movement of said breaker, means responsive to the-relative strength of said spring means with respect to its original strength for preventing reset movement of said spring means when the latter has had its potential energy reduced to an undesirable extent, and an externally visible indicator automatically moved on release or reset movement of said spring means for indicating the nature of the latest movement of said means, and also for indicating when, if at all, the spring means has had its potential energy reduced to an undesirable extent.

3. An automatically releasing and resetting circuit protecting breaker including an enclos ing casing, an automatically operating spring means for 'efiecting release and reset cyclic movement of said breaker, means responsive to the relative strength of said spring means with respect to its original strength for preventing reset movement of said spring means when the latter' has had its potential energy reduced to an undesirable extent, and constructed to cause the breaker parts to remain in released position until sufiicient potential energy is restored to said spring means, and an externally visable indicator automatically moved on release or reset movement of said spring means for indicating the nature of the latest movement of said means, and also for indicating when, if at all, the spring means has had its potential energy reduced to an undesirable extent.

4. An automatically releasing and resetting circuit protecting breaker including an enclosing casing, an automatically operating spring means for effecting release and reset cyclic movement of said breaker, and an externally visible indicator automatically moved on release or reset movement of said spring means for indicating the nature of the latest movement of said means, and also for indicating when, if at all, the spring means has had its potential energy reduced to an undesirable extent, the indicator having two release positions, one of which indicates merely the fact of release, and the other of which indicates the fact of release, and, in addition, the necessity for restoring potential energy to the spring means, and one reset position which indicates the fact of reset.

5. An automatically releasing and resetting circuit protecting breaker including an enclosing casing, an automatically operating spring means for efiecting release and reset cyclic movement of said breaker, means responsive to the relative strength of said spring means with respect to its original strength for preventing reset movement of said spring means when the latter has had its potential energy reduced to an undesirable ex-.

tent, and constructed to cause the breaker parts to remain in released position until sufficient potential energy is restored to said spring means, and an externally visible indicator automatically moved on release or reset movement of said spring means for indicating the nature of the latest movement of said means, and also for indicating when, if at' all, the spring means has had its potential energy reduced to an undesirable extent, the indicator having two release positions,

one of whichindicates merely the fact of release, and the other of which indicates the fact of release, and, in addition, the necessity for restoring potential energy to the spring means, and one reset position which indicates the fact of reset.

6. In an automatically releasing and resetting circuit protecting device, automatic means for releasing and resetting said device, and means responsive to the relative strength of said automatic means with respect to its original strength for inhibiting resetting operation thereof when the latter has been weakened to a predetermined extent, and for maintaining the device in released condition, and for indicating not only the fact but also the reason for thedevice being in such released condition.

7. In an automatically releasing and resetting circuit protecting device, automatic means for releasing and resetting said device and means responsive to the relative strength of said automatic means with respect to its original strength for inhibiting resetting operation thereof when the latter has been weakened to a predetermined extent, and for maintaining the device in released condition, and for indicating not only the fact but also the reason for the device being in such released condition, the inhibiting means being adjustable to vary the amount of weakening of the automatic means necessary to cause the operation of the inhibiting means.

8. In an automatic releasing and resetting circuit breaker, automatic releasing and resetting means, means responsive to the relative strength thereof with respect to its original strength for inhibiting resetting operation thereof when the latter has been weakened to a predetermined extent and for maintaining the breaker released, the inhibiting means being adjustable to vary the amount of weakening of the automatic means necessary to cause the operation of the inhibiting means, and thus to vary the number of cycles of release and reset that will take place before the breaker is maintained released.

9. In an automatic releasing and resetting circuit breaker, a spring constantly tending to create cyclic release and reset movement of the parts thereof, and a latch for inhibiting resetting movement of the parts, after cyclic movement had started, said latch being controlled by the relative condition of said spring with respect to its original condition and being rendered operable to inhibit reset when the spring has been sufliciently weakened from the condition it had before the spring started the immediately preceding cycle of release and reset, and manually operable means operable after the latch has been rendered operable for inhibiting reset to release said latch and thereby permit said spring to cause reset.

10. In an automatically releasing and resetting circuit protecting device, automatic means for releasing and resetting said device, and means responsive to the relative strength of said autocondition.

y 11. In an automatically releasing and resetting circuit protecting device, automatic means for releasing and resetting said device, and constructed to lose strength as it operates, and means responsive to the relative strength of said automatic means with respect to its original strength for inhibiting resetting operation thereof when the latter has been weakened to'a predetermined extent, and for maintaining the device in released condition.

12. In an automatically releasing and resetting circuit protecting device, automatic means for releasing and resetting said .device, and constructed to lose strength as it operates, and means responsive tothe relative strength of said automatic, means with respect to its original strength for indicating the fact that said automatic means has lost a predetermined amount of strength, said indicating means also serving to inhibit resetting operation of said automatic means when the lat- 75 has lost a predetermined amount of strength, said indicating means also serving to inhibit resetting operation of said automatic means when the latter has lost the predetermined amount of strength and also serving to indicate, when such be the case, that the breaker is held released by the fact that the automatic means thereof has lost the predetermined amount of strength.

' WILLIAM H. FRANK.

CERTIFICATE OF CORRECTION.

Patent NO. 2,036,266.

April 7, 1936..

WILLIAM H. FRANK.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 11, for "spring" read frame; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office Signed and sealed this 5th day of May, A. D. 1936.,

(Seal) Leslie Frazer Acting Commissioner of Patents. 

